I reviewed the SVG 1.2 specification for WAI-PF. Please incorporate these
comments into:
http://www.w3.org/WAI/UA/2004-11-wai-comments-svg12.html
There are some significant improvements in SVG's accessibility in 1.2.
There are some concerns which should be addressed to support dynamic
markup.
1. Focus - What elements is the Focusable property applicable to? Having
the focusable property is a big plus for accessibility. This allows
JavaScript to request that an element receive focus as long as the
attributes is set.
2. sXBL and the Roadmap - sXBL provides a mechanism to theoretically define
improved semantics through the creation of xbl definitions. They are also
capable of defining what events get triggered by these new higher level
document constructs.
What they do not do is define how the user agent maps these definitions to
the accessibility interoperability layer. Basically, the definitions are
adHoc and do not provide pre-defined mappings to standard Accessible roles
on the target platform. An assistive technology would have to guess what
the purpose of these definitions are. Also, there is inadequate state
information capable of support dynamic web content.
3. nav-index: Although this was also included in CSS3, we replaced this
with nextfocus attribute in xhtml 2. Please look at what the xhtml 2
working group has done with next focus.
4. If sXBL is not employed, how are semantics like role information derived
for the assistive technolgy? See the DHTML accessibility roadmap.
5. State information - Accessibility is dependent on knowledge of state
data (expanded, collapsed, checked, required, etc.) Is this information
declarative in all cases? In xhtml 2, XForms and its model are tightly
integrated whereby the XForms data model is bound to elements from which we
can acquire the state data. SVG 1.2 is not specified as such.
6. event handlers:
The event handlers look like xml event handlers but it is not clear. XML
events has a handler <description> which will be used to help with
accessibility to tell the assistive technology what the purpose of the
handler is. This is essential.
7. acces keys:
In xhtml 2 we are desiging a repacement for access key which provides for
device independent binding as well as a description for accessibility. It
also provides for binding of multiple condition types (device mappings).
Currently, this is in the form of the <access> tag. How is this being
addressed in SVG 1.2? The user agent needs to be able to provide a list of
access mappings with descriptions to the user (shortcuts, accelerators,
etc.)
8. Note: In section 1.2 of the sXBL specification you have DOM extension
for sXBL. This is essential for accessibility.
Rich Schwerdtfeger
STSM, Software Group Accessibility Strategist/Master Inventor
Emerging Internet Technologies
Chair, IBM Accessibility Architecture Review Board
schwer@us.ibm.com, Phone: 512-838-4593,T/L: 678-4593
"Two roads diverged in a wood, and I -
I took the one less traveled by, and that has made all the difference.",
Frost